Sawmill

ABSTRACT

A sawmill having a saw blade  11  which can move between a substantially horizontal cutting position and a substantially vertical cutting position, the sawmill having a control arm  14  which operates to move the blade between the substantially horizontal and vertical cutting positions, the control arm  14  being mounted for pivotal movement about an axis  15,  there being mechanism  18  which acts against the control arm in a substantially linear manner, wherein movement of the mechanism causes the control  14  arm to pivot about the axis  15  and move the blade  11  between the cutting positions. The sawmill may have a deflector in the form of a flap mounted adjacent the blade to deflect a cut board from the log as the next board is being cut.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to PCT/NZ03/00101, filed May 23, 2003,entitled A SAWMILL. The entire content of it is incorporated herein by areference.

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

FIELD OF THE INVENTION

This invention relates to sawmills generally, but has particularapplication with portable sawmills.

BACKGROUND

It is known to use portable sawmills to mill logs at remote locations.Examples of prior art sawmills are shown in the patent specifications GB2,212,101 (Peterson), WO 97/35697 (Peterson Portable), 248548/250983(Peterson Portable), U.S. Pat. No. 5,046,391 (Lewis), and U.S. Pat. No.5,819,626 (Lucas). These prior art sawmills each have various advantagesand disadvantages. It is an object of the present invention to providefurther options for sawmilling, or to at least provide the public with auseful choice.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a sawmillhaving a saw blade which can move between a substantially horizontalcutting position and a substantially vertical cutting position, thesawmill having a control arm which operates to move the blade betweenthe substantially horizontal and vertical cutting positions, the controlarm being mounted for pivotal movement about an axis, there being runnermeans which runs along a side part of the control arm to push thecontrol arm to cause the control arm to pivot about the axis and movethe blade between the cutting positions; the runner means being suchthat it is able to cause the control arm to move to one of the cuttingpositons at which time it bears against the control arm to lock theblade in that position.

Preferably the sawmill has means to provide force to move the runnermeans.

Preferably the runner means moves in a linear non-swinging manner as thecontrol arm pivots.

Preferably the side part of the control arm provides an at leastpartially curved raceway against which the runner means runs when theblade is moved between the cutting positions.

Preferably the side part of the control arm provides a raceway againstwhich the runner means runs when the blade is moved between the cuttingpositions, and wherein the runner means comprises a roller.

Preferably the side part of the control arm provides a raceway againstwhich the runner means runs when the blade is moved between the cuttingpositions, and wherein the runner means comprises a roller bearing.

Preferably the side part of the control arm provides an at leastpartially curved raceway against which the runner means runs as theblade is moving between the cutting positions, the control arm having asecond side part, the first and second mentioned side parts each havinga flared portion and wherein the runner means can be moved to bear downagainst the flared portions in turn to lock the blade in one of the twocutting positions respectively.

Preferably the side part of the control arm provides an at leastpartially curved raceway against which the runner means runs as theblade is moving between the cutting positions, the control arm having asecond side part, the first and second mentioned side parts each havinga flared portion and wherein the runner means can be moved to bear downagainst the flared portions in turn to lock the blade in one of the twocutting positions respectively, and wherein the runner means comprises apair of rollers each of which is able to bear down upon a respectivedifferent one of the flared portions.

According to a further aspect of the invention there is provided asawmill having a saw blade which can move between a substantiallyhorizontal cutting position and a substantially vertical cuttingposition, the sawmill having a control arm which operates to move theblade between the substantially horizontal and vertical cuttingpositions, the control arm having a pair of oppositely disposed sideparts each with a flared part, the control arm mounted for pivotalmovement about an axis, there being runner means comprising a rollerwhich is able to run along one of the side parts of the control arm topush the control arm to cause the control arm to pivot about the axisand move the blade between the cutting positions and then bear downagainst one of the flared parts to lock the blade in one of the cuttingpositions, and wherein the roller means is able to subsequently beardown on the other flared part to lock the blade in the other cuttingposition.

Preferably the one of the side parts that the roller is able to runalong provides an at least partially curved raceway for that roller.

Preferably the roller means comprises a pair of rollers arranged suchthat one roller can bear down on one of the flared parts and the otherroller can subsequently bear down on the other flared part to lock theblade in the cutting positions respectively.

DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood, and so thatfurther features thereof may be appreciated, some embodiments of theinvention will now be described, by way of example, with reference tothe accompanying drawings, in which:

FIG. 1 illustrates a portable sawmill in accordance with one embodimentof the invention,

FIG. 2 illustrates a blade moving arrangement of the sawmill showing asaw blade in a vertical cutting position,

FIG. 3 illustrates the blade moving arrangement with the blade intransition between the vertical cutting position and a horizontalcutting position,

FIG. 4 illustrates the blade moving arrangement when the blade hasarrived in the horizontal cutting position,

FIG. 5 illustrates a power mechanism for the blade moving arrangement,

FIG. 6 illustrates, schematically, the manner of movement of the bladebetween the vertical and horizontal cutting positions,

FIG. 7 illustrates a board removal system of the sawmill,

FIG. 8 further illustrates the board removal system,

FIG. 9 illustrates the board removal system showing the blade in thevertical cutting position,

FIG. 10 illustrates the board removal system showing the blade intransition, and

FIG. 11 illustrates the board removal system showing the blade in thehorizontal cutting position.

DETAILED DESCRIPTION

With reference to FIG. 1, a portable sawmill includes a carriage 1arranged to be supported upon spaced apart tracks 2 and 3 to co-operatewith wheels or rollers 4 mounted at the base or top of the carriage. Thetracks 2 and 3 may be supported on skids 5.

The carriage 1 comprises two spaced apart rectangular end frames 6. Eachend frame 6 comprises a pair of spaced apart tubular uprights 7connected by an upper cross member 8 and a lower cross member 9. Asubstantially rectangular carriage deck 10, that extends, in use,between the end frames 6, is located for upward and downward movementrelative to the uprights 7 by way of bushings (not shown). An example ofsuitable bushings is given in WO 97/35697.

The carriage deck 10 comprises means for mounting a saw with a circularblade 11, of which suitable means are described in the patentspecifications GB-A-2212101, NZ 248548/250983, and WO 97/35697. One ofthe tracks 3 may be in a raised position co-operating with carriagewheels 4 mounted at the upper portion of one end frame 6. As sawdust isexpelled to this side, this arrangement avoids interference caused bysawdust build-up around the low track. It also facilitates loading logsunder the high track 3 into the mill, reducing the danger of damage tothe tracks, during this operation. The carriage 1 comprises drivemechanisms allowing vertical movement of the carriage deck 10 andhorizontal or sideways movement of the saw.

With further reference to FIG. 1, when the sawmill is in use it isarranged with a log 13 between the end frames 6 of the carriage andbelow the carriage deck 10. The carriage 1 is then run along the tracks2 and 3 so that the saw blade 11 makes a vertical cut in the log 13. Thesaw blade 11 is then moved through 90 degrees to assume a horizontalorientation, and the carriage, and thus the blade 11, is moved backalong the log to make a horizontal cut which intersects the first cut.In this way a board is cut from the log. The blade 11 is then set backto a vertical orientation, is moved sideways as desired, and the processis repeated continuously until the log is substantially milled into anumber of boards. It will of-course be appreciated that the carriagedeck 10 is moved downwards during milling after each complete row ofboards is cut from the log. Preferably the carriage is clamped as at 9 a(FIG. 1), or otherwise secured, to a chain drive or cable drive tofacilitate movement of the carriage along the track.

FIGS. 2, 3 and 4 show the means for moving the blade 11 between thevertical and horizontal orientations or cutting positions. Rotary poweris provided to drive the blade 11 by way of a motor 11 a. Referring toFIG. 2, the blade 11 is shown set in the vertical cutting position. Theblade is mounted on a control arm 14, a medial part of which is in turnmounted for pivotal movement as at 15. The end of the control arm remotefrom the blade has flared side walls 16 and 17 opposite one another. Asshown in FIG. 2, an operating means, comprising a block 18 slideable ona lineal rail 19 is immediately adjacent the left hand side flared wall16. The block 18 has two roller bearings 20 set side by side, and fixedagainst movement other than when they move linearly with the rest of theblock. The left hand roller bearing is positioned on top of and againstthe left hand side wall 16 when the blade 11 is in the vertical cuttingposition. This serves to lock the control arm 14, and thus the blade 11in that position.

When it is desired to move the blade 11 to the horizontal cuttingposition the bock 18 is driven along the lineal rail 19 in a verticalmotion to move the left hand bearing away from the left hand side wall16. This unlocks the control arm 14 and allows it to pivot to swing theblade as shown in FIG. 3. The block 18 continues to move until the righthand bearing is positioned against and above the right hand side wall 17as shown in FIG. 4. This serves to lock the control arm 14 with theblade 11 in the horizontal cutting position. Preferably when the bladeis in the horizontal cutting position it can be used to make ahorizontal cut from either side of the control arm.

Those skilled in the art will appreciate that movement of the block 18in the reverse direction will return the blade 11 to the verticalcutting position. For the blade to reach the vertical cutting positionthe control arm 14 cannot simply be left to swing under gravity, butrather must be forced to move by the block 18, and more particularly bythe left hand bearing. In this regard the left hand bearing contacts andruns along the left hand wall 16 to force the control arm around. Tofacilitate this the left hand side wall 16 has a curved section whichprovides a raceway 16 a for the left hand bearing.

FIG. 5 shows an embodiment of the invention which incorporates a chaindrive arrangement 21 used to provide a driving force to move the block18 along the lineal rail 19. It should however be appreciated that otherdrive arrangements can be utilized, and in some alternative embodimentsthe block may be moved manually.

FIG. 6 illustrates, schematically, the movement of the control arm 14and thus the blade 11.

It will be appreciated by those skilled in the art that the sawmilldescribed above provides a linear movement arrangement for moving theblade 11 between vertical and horizontal cutting positions, which isboth easy to control and also offers a positive locking means. Toappropriately limit the lineal movement of the block 18 and the bearings20 the sawmill has suitable stoppers positioned at the points marked 22in FIG. 2. The stoppers may be mechanical, electrical, or pneumatic,etc, in nature

In one embodiment of the present invention there is provided means forremoving a cut board from a log as the next board is being cut by aswing blade sawmill. This avoids down-time resulting from having toremove a cut board from the log by hand.

Referring to FIG. 7, board removal is achieved by way of a deflector inthe form of a flap 23 mounted for sliding movement on rods 24 adjacentthe front or rear of the saw blade 11. The flap 23 will be mountedadjacent the front or rear of the blade 11 depending on which end of thesawmill the operator wishes the cut boards to be deposited. Thedeflector can be used in connection with vertical or horizontal sawcuts. The arrangement is such that when a board has been cut in the logit remains in place until the next board is being cut. As that nextboard is being cut, with the carriage 1 moving along the log, the flap23 contacts the board already cut and deflects/pushes it to an end ofthe sawmill. To facilitate this the carriage is preferably motor driven.

FIG. 7 shows the position of the flap 23 in relation to the blade 11when the blade is in the substantially vertical cutting position. FIG. 8shows the position of the flap 23 when the blade 11 is in the horizontalcutting position. The flap 23 is suspended alongside the blade 11 whenthe blade is in the substantially vertical cutting position. The flap 23is suspended above the blade 11 when the blade is in the horizontalcutting position. As shown, the flap 23 does not overhang the wholewidth of the blade 11 when in the horizontal cutting position. The widthof the blade that the flap 23 does not overhang is used to cut the nextboard in the log 13.

The flap 23 can be adjusted laterally in the left or right directionalong the rods 24. This allows adjustment to position the flap 23 at theend of a board that has been cut, and allows adjustments for differentsized boards. The operator will set the board remover flap 23 adjacentthe edge of the board currently being cut. The part of the blade 11 thatis not overhung by the flap 23 will be used to cut the next board.

In one embodiment of the invention the flap 23 is associated with thesaw side-ways movement facility of the saw such that when the blademoves sideways the flap 23 moves side-ways by substantially the samedistance, but in the opposite direction. This may allow space for asubsequent cut and allow the flap to work against the board just cut.

Preferably a rule or gauge is mounted on at least one of the rods 24 toaid with accurate positioning of the flap 23. Preferably the rods areassociated with a power mechanism 25 to mechanically move the flap 23along the rods, although this is not essential. In some embodiments ofthe invention the rods 24 may be threaded and driven by a DC motor forautomatic setting, etc. Alternatively the flap 23 may be positionedmanually and locked in place by a locking means such as a star knob orthe like.

The flap 23 is preferably not free to hinge on any of the rods 24, butin some other embodiments of the invention it may be hinged so that itcan be raised and lowered as required. The flap is preferably made ofmetal, although it could be made from other suitable durable materials.

As discussed above, the removal system is designed so that the flappushes the cut board from the log as the blade makes the next cut in thelog while the carriage travels. When the blade reaches the end of thelog, the cut board is pushed clear from the log. The blade is thenflipped to the vertical position to make a further cut in the board, indoing so the flap will be positioned so that it runs alongside the boardbeing cut, and the carriage moves once again. Once the saw reaches theend of the log, the blade will be flipped to the horizontal position tocut the next board, simultaneously causing the flap to be positioned toremove the cut board when the carriage moves again.

FIGS. 9, 10 and 11 show the flap in various dispositions relative to thesaw blade 11.

It will be appreciated that in some embodiments of the invention theflap 23 may be used as a guide as to the depth of a cut. In someembodiments the flap 23 may be capable of vertical adjustment tofacilitate removal of a cut board above that being cut at the time.

In some embodiments of the invention the sawmill movement of thecarriage 1, the sub carriage 10, the control arm 14, and the flap 23 maybe achieved by one or more motors. The motor or motors may be controlledby a CPU so that direction, speed, or degree of movement of the abovecomponents can be set or regulated as desired. Preferably the sawmill issuch that when the cutting speed of the blade changes significantlyduring cutting, the speed of the carriage 1 along the tracks 2 and 3 isautomatically modified proportionately. For example, if the saw islaboring, and is thus moving more slowly while cutting a hard part of alog, then the speed of the carriage 1 along the tracks 2 and 3 isautomatically reduced to allow the blade more time on that particularpart of the log. When the blade speed subsequently increases thecarriage automatically speeds up as it moves along the tracks.

While some preferred forms of the invention have been described herein,it should be appreciated that modifications and improvements can occurwithout departing from the scope of the following claims.

1. A sawmill having a saw blade which can move between a substantiallyhorizontal cutting position and a substantially vertical cuttingposition, the sawmill having a control arm which operates to move theblade between the substantially horizontal and vertical cuttingpositions, the control arm being mounted for pivotal movement about anaxis, there being runner means which runs along a side part of thecontrol arm to push the control arm to cause the control arm to pivotabout the axis and move the blade between the cutting positions; therunner means being such that it is able to cause the control arm to moveto one of the cutting positions at which time it bears against thecontrol arm to lock the blade in that position; the sawmill formed suchthat the side part of the control arm provides a raceway against whichthe runner means runs as the blade is moving between the cuttingpositions, the control arm having a second side part, the first andsecond mentioned side parts each having a flared portion and wherein therunner means can be moved to bear down against the flared portions inturn to lock the blade in one of the two cutting positions respectively.2. A sawmill according to claim 1, wherein the sawmill has means toprovide force to move the runner means.
 3. A sawmill according to claim1, wherein the runner means moves in a linear non-swinging manner as thecontrol arm pivots.
 4. A sawmill according to claim 1, wherein theraceway is at least partially curved.
 5. A sawmill according to claim 1,wherein the runner means comprises a roller.
 6. A sawmill according toclaim 1, wherein the runner means comprises a roller bearing.
 7. Asawmill according to claim 1, wherein the runner means comprises a pairof rollers each of which is able to bear down upon a respectivedifferent one of the flared portions.
 8. A sawmill according to claim 7,wherein the runner means moves in a linear non-swinging manner as thecontrol arm pivots.
 9. A sawmill having a saw blade which can movebetween a substantially horizontal cutting position and a substantiallyvertical cuffing position, the sawmill having a control arm whichoperates to move the blade between the substantially horizontal andvertical cutting positions, the control arm having a pair of oppositelydisposed side parts each with a flared part, the control arm mounted forpivotal movement about an axis, there being runner means comprising aroller which is able to run along one of the side parts of the controlarm to push the control arm to cause the control arm to pivot about theaxis and move the blade between the cuffing positions and then bear downagainst one of the flared parts to lock the blade in one of the cuttingpositions, and wherein the roller means is able to subsequently beardown on the other flared part to lock the blade in the other cuttingposition.
 10. A sawmill according to claim 9, wherein the one of theside parts that the roller is able to run along provides an at leastpartially curved raceway for that roller.
 11. A sawmill according toclaim 9, wherein the roller means comprises a pair of rollers arrangedsuch that one roller can bear down on one of the flared parts and theother roller can subsequently bear down on the other flared part to lockthe blade in the cutting positions respectively.
 12. A sawmill accordingto claim 9, wherein the runner means moves in a linear non-swingingmanner as the control arm pivots.